


the square root of infinity

by firebrands



Category: Marvel Cinematic Universe
Genre: Angst, Domestic Fluff, Established Relationship, Insecurity, Jealousy, M/M, POV Tony Stark, Panic Attacks, Pre-Captain America: Civil War (Movie), Steve Rogers Feels, Tony Stark Has Issues, Tony Stark Needs a Hug
Language: English
Status: Completed
Published: 2020-12-07
Updated: 2020-12-07
Packaged: 2021-03-10 05:48:59
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,795
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27939968
Author URL: https://archiveofourown.org/users/firebrands/pseuds/firebrands
Summary: steve and tony have their first fight. tony doesn't handle it well.
Relationships: Steve Rogers/Tony Stark
Comments: 19
Kudos: 294





	the square root of infinity

**Author's Note:**

  * For [maguna_stxrk](https://archiveofourown.org/users/maguna_stxrk/gifts).



> well hello, it's been a minute.
> 
> sometimes you just want to write something warm and familiar. i thought i'd forgotten how.
> 
> this is for earl - i'm sorry this is so late. it's not exactly what you wanted, but it's a lot of angst! i hope you enjoy it regardless. :)
> 
> thank you [peach](https://archiveofourown.org/users/ohjustpeachy/works) for the beta. i love you so much!

Tony finds out with his hands deep in JARVIS’ code. Former-JARVIS, actual-JARVIS, he hasn’t really decided on what to refer to the mess of numbers of letters that formed his former AI, and now, well—Vision, too. It’s all a mess, really, and Tony wanted something simple to do with his hands, minimal focus, low-risk.

He should have known better, really. Nothing about him, his work, his _life_ , has ever been low-risk.

It’s a command from Steve with a privacy protocol. Search, identify, and surveil Sergeant James “Bucky” Barnes, also known as The Winter Soldier. Missing, found, and missing again as of six months ago. Tony frowns at the monitor. He knows he hasn’t read it wrong, but can’t believe it; he reads it again.

Somehow, in the span of time of Steve coming back from Washington, of them settling in together, he’d done this. He’d asked JARVIS to do this for him, and keep it from Tony.

Tony leans back against his chair. “FRI,” he says.

His new AI chirps to life. “Boss?”

“Gimme everything JARVIS found on this.”

“It’s on your phone now, boss.” In front of him, a hologram materializes as well, displaying hundreds of photos, grainy and filtered, and copies of reports on sightings. Tony stands up, takes a step back and frowns some more. He opens his mouth a few times, borne of his need to verbalize even without anyone listening; he’s angry. He’s more shocked than angry, but the anger is there, low and simmering.

Beneath it, though, is a grain of doubt: Why? Why did he keep it hidden? Especially now—after all the truth came spilling out of them, crystallizing into something Tony held dear. And after all Steve had said, about keeping secrets, about _trust_. He briefly considers asking FRIDAY to print it all out, just so he can throw the sheaf of paper in front of Steve and demand: _what the fuck_ , but he’s better now, more mature. Or so he likes to tell himself.

So instead, he walks to the penthouse and finds Steve reading.

Tony clears his throat.

Steve looks up. “Hey,” he says, setting his book down. “You done working?”

Tony smiles, pained and tight. “So,” he says, sitting at the foot of the bed. “Bucky.”

Steve’s eyebrows meet, looking concerned. “What about him?”

Tony shuts his eyes and counts backward from five. “Why didn’t you just tell me?”

Steve inches closer to him and rests his hand on Tony’s knee. Tony doesn’t open his eyes.

“I didn’t want to worry you,” Steve says very quietly.

Tony’s eyes fly open, the anger now boiling over. “Oh is that it?” He asks sarcastically. “So you decided to use JARVIS—without _my_ permission, to look for him?”

Steve’s mouth works, and he looks genuinely shocked. “You said I could talk to JARVIS.”

“That’s not the point!” He pushes Steve’s hand off him and stands. “Why would you keep that a secret?”

“I—I didn’t,” Steve says haltingly. “I wasn’t thinking. I just wanted to know if JARVIS could find him, but I knew it was almost impossible anyway, so there was no real point—”

“If there was no point,” Tony says, voice lowering, “then why’d you do it?”

“Tony,” Steve stands now, too, tries to reach out and touch Tony’s elbow, to disentangle Tony’s arms that have crossed over his chest on their own volition. “He’s my best friend. I’m worried about him. I just thought it was something I should do myself.”

Tony nods, not really listening. His head is swimming with what he thinks could be actual reasons why Steve had kept this from him. A tangled mess of fear and insecurity, then shock at his ability to be aware of it. Is this maturity? He doesn’t like it much. Better if it stayed Steve’s fault—and it is Steve’s fault, it is. But maybe Tony doesn’t need to work himself up like this. But then again, Tony’s already worked up. “Stop,” Tony grinds out.

So Steve stops, a foot away from Tony, looking more scared than Tony’s ever seen him.

“I’m going to go.”

“Don’t.”

Tony looks up at Steve. He hadn’t even realized he’d looked away. Steve takes a deep breath, closes the space between them, and takes Tony’s hands in his.

Tony sighs.

Steve threads their fingers together, squeezes Tony’s palms. “Hey.”

“Hi.”

“Do you want to talk about it?”

“No.”

“Want to say more than one syllable, maybe?”

A joke? Now? Tony feels his frown deepen.

“No.”

“Is this a fight?”

Tony looks up at him. “A fight means you don’t think you should be sorry.”

“Now, hold on a second,” Steve says, a small frown beginning to form on his face. Barely perceptible, if you didn’t know the signs. “I already explained why—”

“And that’s supposed to make it okay?”

“Where is this coming from?” Steve asks, letting go of Tony’s hands, which means he’s mad too, which drives Tony _insane_.

“Are you fucking kidding me?”

“There’s no need to raise your tone—”

“Don’t fucking use your de-escalation tactics on me.” Tony hisses, turns on his heel, and walks out the door. He gives himself the satisfaction of slamming it shut.

* * *

The next few days are filled with small acts of penitence: a cup of coffee on the bedside table when Tony wakes, a sandwich in the workshop, a completed report for a day-old mishap. It’s on Thursday that Tony’s heart finally softens. Over nothing, really, just a small doodle on his desk. He realizes, in that moment, that of all his achievements, perhaps learning to understand Steve Rogers should rank highest. Right up there with being understood by him, too.

Tony’s lying in bed, reading a report on his tablet, when Steve peeks in.

“Hey.” He sounds tentative.

Tony sighs, sets his tablet aside, and takes off his glasses. “Well, come in.”

Steve’s barely able to hide his grin, and nearly bowls Tony over when he hugs him. “Hi,” Steve says, burying his nose against Tony’s neck.

“Hello to you too, you overgrown labrador,” Tony laughs, pushing Steve away a little lest he be crushed under all combined weight of supersoldier and three bowls of pasta that Clint prepared for dinner.

“I _missed_ you,” Steve says, hugging Tony closer to him. He looks up at Tony, resting his chin right on Tony’s sternum. “Was that our first fight?”

Tony snorts. “Unlikely to be our last,” he says.

“Hey,” Steve chides, leaning up and brushing Tony’s nose with his. “Don’t say that.”

“It’s true. Anyway,” Tony leans closer, brushes their lips together. “Make it up to me.”

Steve arches an eyebrow.

“Don’t start,” Tony warns.

Steve huffs out a laugh, tips them over until they’re lying down, and makes it up to him.

* * *

As a man of science, it behooves Tony to conduct experiments and to test hypotheses.

First, identify the problem.

Second, conduct research.

Third, develop a hypothesis: follow if / then structure.

Fourth, test through experiments: ensure factors are varied one at a time.

Fifth and final, draw a conclusion.

Tony’s tapping the tip of a screwdriver against his bottom lip as he thinks, and then two strong arms wrap around his waist and just like that, the problem has identified itself.

(One frustrating blind spot in Tony’s life: relationships. Which isn’t to say he hasn’t tried to make sense of them, sped read through self-help books and trawled through Reddit. Unlike everything else, research pales in comparison to experience, and there’s only so much he can do to make sure this one precious thing in his life is perfect.)

“Busy?” Steve presses a small kiss on the back of Tony’s neck. Tony can barely suppress a shiver.

He wants to say, _I was, until you showed up_. It doesn’t just apply to this moment. That fact shouldn’t hurt.

Instead, Tony says: “Yeah, kinda.”

“Okay,” Steve says easily, pulling away. He comes back to press a quick kiss to Tony’s cheek. “See you later?”

“Yup,” Tony says, and okay. Maybe he needs to spend a day or two really figuring out who the problem is, here. (It’s him. He knows this. He’s always the problem.)

Two days later, Tony settles on having to review related literature. In this case, this means sitting alone in the workshop as he relives every moment when Steve was distracted. Was that a sign? In a brief moment of clarity, Tony asks: “Fri, am I crazy?”

“Signs point to no, boss. But I can pull up recent results on the search engines?”

“I’d rather not hear what the general public thinks, thanks,” Tony says, sighing. He rests his face in his hands. It’s not like he meant to think of this—what is wrong with his brain, that the intrusive thoughts come in the form of the few moments he’d asked Steve what was on his mind, only to be brushed off?

What did that mean?

Did it matter?

Step three: if that was a sign, then there was a problem.

If that wasn’t a sign, then there wasn’t a problem.

If Tony didn’t figure this out, then there would definitely be a problem.

This isn’t how a hypothesis is meant to sound. Tony’s a terrible scientist.

“Fri, call Bruce.”

“Tony?” Bruce’s voice is rough. He sounds annoyed.

“Hey, seven PhDs, how do I form a proper hypothesis?”

“Fuck you, Stark.” The line clicks off.

Tony turns his wrist, checks his watch. Three AM? Figures.

He stretches out his back. “Friday,” he says, standing up. “The search functions for Barnes.”

“On it, boss.”

“Atta girl.”

* * *

Try as Tony might—and he’s _trying_ , which in itself feels like a failure, because Tony stark _does_ or _does not_ and there is no need to attempt—he feels like something has shifted between them, and he doesn’t know how to fix it.

Maybe he’s just making it all up in his head. That’s the easy solution, isn’t it? And that’s usually the answer: start with the easiest answer and work your way up. He can already see Natasha rolling her eyes at him. _Maybe the solution is to stop treating your relationship like it’s quantum theory_.

Steve’s hand is on his lower back, steering him inside a restaurant. He thinks only of what Steve said, all those weeks ago: _I had to do it myself_.

Tony wants to argue, right this moment. But how can he? It’s awful that they can be so alike. The only reason he keeps his mouth shut is because he knows that Tony’s used that argument before. Maybe this is growth, to know when to back down from a fight. Or to avoid one totally.

Steve reaches over the table, brushes his fingers over Tony’s wrist. “You okay?”

There are a lot of answers to that. Tony settles on the truth. “Not really.”

Steve’s brow creases with worry. “What’s wrong?”

Again: an infinite multiverse of answers to answer a question that simple. With this, Tony does struggle for a moment, and the next words are much harder to say—they almost feel caught in his throat, like a lump of meat. “I don’t know.”

“You can tell me anything, you know,” Steve says gently. So gentle, it almost breaks him; Tony doesn’t deserve this. Steve doesn’t deserve this.

“I know,” Tony says, and this is him lying through his teeth, and this is what he’s good at, and maybe this is why he’ll never know how relationships are. It’s a trust issue, probably. He doesn’t know if the issue is with Steve, or with himself. “Don’t worry about it.”

Tony tries harder, now: smiles more, eats with gusto. He knocks Steve’s thigh with his knee, looks up at him from under his lashes. This is what life is like for Tony Stark: it’s acting. He knows the approximations to get his point across. As their evening goes on, the small wrinkle on Steve’s forehead smooths out, and maybe Tony wishes he wasn’t so good at pretending.

Maybe he wishes that Steve read him better.

* * *

The moment of epiphany is often described as transcendental.

This one hits like a ton of bricks—literally, because Tony does know what that feels like, and the suit is shock proof, sure, but that shit still fucking hurts, and even in moments of epiphany, somehow he still manages to go off on a tangent. The point remains: Steve’s hand is on his hip, and they’re in bed, and epiphanies usually equate clarity, peace.

Tony freezes up.

“Tony?” Steve murmurs, sliding his hand up Tony’s side.

“I’m sorry,” Tony says, sitting up. “I know I’m being difficult.”

“I didn’t say you were.” Steve sits up beside him, rests his hand on Tony’s shoulder, and turns Tony to look at him. “Who said you were being difficult?”

“Me, I’m saying it,” Tony says. Panic is beginning to bubble in his belly, slowly rising up his throat. Typical of him to mistake a eureka moment with a panic attack. Par for the fucking course for Tony Stark. “I’m being difficult right now.”

“No you’re not,” Steve says, rubbing up and down his arms. “Tony. Look at me.”

Tony breathes out through his mouth, then in through his nose. Steve tips his chin up and meets his gaze.

“Here are the variables,” Tony breathes out, is afraid of what he’ll say next, his brain is fogged over and full of static. “I love you, and I don’t know what to do with that.”

Steve takes a deep breath, takes Tony’s face in his hands. “Here’s a constant,” he whispers, breath warm on Tony’s cheek. “I love you. I love you. You, Tony Stark. I love you.” He kisses Tony, hard and close lipped, more aggressive reminder than affection.

“Okay,” Tony says, because there’s a wild part of him that still thinks—there was a problem, there was a problem and if this is love, then what comes next? If this is constant, then what variable will arrive to change all of that?

Steve kisses Tony again, almost desperate, this time. “Is this about Bucky?” Tony sucks in a breath at the question, horrified at being discovered. Steve hums, then he runs one hand down Tony’s back, up his arm, down his side. A reminder of his presence. Tony is suddenly grateful for it.

“And if it is?” he murmurs.

“Tony,” and somehow, Steve sounds _fond_ , which throws a wrench in this whole debacle, and deep in the recesses of Tony’s brain, rationality begins to take root. “He’s my best friend. You’re the love of my life.”

Tony breathes.

“Did you hear me? You. You’re the love of my life. Please don’t make me compare,” Steve huffs out a small laugh, and it warms Tony all over, like sunshine peeking through the clouds after a strong rain. “And maybe you don’t believe me just yet,” Steve touches their foreheads together, then rubs his nose against Tony’s, the affection plain and chaste. It makes Tony feel more loved than he’s ever felt in his life—not that there were many moments to compare against, but still.

“I feel a little crazy,” Tony says, finding it in himself to smile up at Steve.

“A little crazy in love?” Steve asks, grinning.

“I can’t believe you just made a Beyonce reference. In the middle of my panic attack.”

Steve bites his bottom lip, a poor attempt at stopping himself from laughing. Tony flicks his forehead. “Say it again,” Tony says, and his smile still feels a little wobbly, but it’s a step.

“Crazy in Love?” Steve asks, pulling Tony close and wrapping his arms around Tony’s waist.

It’s an odd angle, and eventually Steve shifts to lift Tony up onto his lap. “Ass,” Tony says. “You know what I meant.”

Steve smiles again, right before pressing a kiss to Tony’s shoulder. “Step one,” he says. “The problem is you’re afraid I don’t love you. Step two: find out how to show you that I do.” He pauses, and Tony feels breathless as he presses another kiss to Tony’s bare skin. “Step three. Hypothesis? If I show Tony I love him all the time, then eventually he’ll believe me.”

“Sounds like a shaky hypothesis,” Tony says, but his voice quivers a little as he says it. He can’t explain how he feels, other than warm in Steve’s embrace.

Steve tuts. “Step four, experimentation. Small gestures, date nights.” Steve rubs Tony’s back as he speaks, and stops to tilt Tony’s head up to face him. “Am I getting this right?”

Tony smiles. “I don’t know, what’s the conclusion?”

Steve wraps his arms around Tony’s waist once more. “You’re here. I’m here. I love you.” He leans up, brushes their lips together. “Is that enough?”


End file.
